Talk:Climate change feedbacks

Cleanup and references

Cleaned up some refs and code, switched some to LDR, others to {{Cite doi}}. We're using the latest AFAIK. Some references I think could be improved. For example, #2 from the University of Texas are lecture notes, and #4 is about planetary science in general—not really focused on climate change feedback.[1] ChyranandChloe (talk)

What to include in block diagram graphic

The "Negative feedbacks" section of the graphic has been re-worked in new Version 5 (05:54, 20 July 2023). —RCraig09 (talk) 06:01, 20 July 2023 (UTC)

@Sjsmith757, InformationToKnowledge, Dtetta, and Femke: Requesting concise input on what wording to include in this diagram. There may be some subtleties on what different sources define as a climate feedback per se (versus a parallel process), but let's define concisely what to include in the diagram with minimal theoretical digressions if possible. Specific wording is key at this point, keeping in mind space limitations in the graphic. —RCraig09 (talk) 21:50, 21 July 2023 (UTC)

• · The key here for me is making sure the image is accessible. I have difficulty reading the small font, especially in blue. The title can become "climate change feedbacks". CO₂ can be used rather than the full carbon diodide. I think we can omit soils for brevity. I would omit the words "positive feedback" and "negative feedback" as jargon (and in the article use the more lay-friendly "self-reinforcing and balancing" feedbacks). I would omit water vapor under Greenhouse gases (and just state CO₂, methane and NO₂), as it's not a forcing but only a feedback.

· The image gives the impression that removal of CO2 by ocean and plants is a "global warming" feedback, rather than a GHG emission feedback. Will require a bit of reshuffling to put this above global warming. Image gives the impression there are as many positive as negative feedbacks, which is not quite correct according to the article. —Femke 🐦 (talk) 09:41, 22 July 2023 (UTC)

Thanks for excellent conciseness. Will deeply consider and implement many, to the extent practical. —RCraig09 (talk) 13:22, 22 July 2023 (UTC)

• · Thanks for your continued efforts to improve this graphic RCraig09. I generally concur with with what Femke has said, although IMO your approach of positive/negative with those terms explained in the caption seems pretty clear -don’t have a strong opinion on this. Agree with Femke it would be better to try and introduce more lay friendly feedback terms into the body of the article. A few additional thoughts:

· On the left column you use “the” a couple of times, but not on the right. Suggest on the right side you describe plants and oceans as removing CO2 from “the” air.

· When you delete water vapor from the greenhouse section, as Femke has suggested, I’m assuming you will redirect the arrow from that text box directly to global warming, correct?

· Although it’s somewhat clear, for the text box on water vapor I might say something like ”increased water vapor in the atmosphere from warming” Dtetta (talk) 14:23, 22 July 2023 (UTC)

Thanks^∞ — I'll try to assimilate everyone's thoughts. —RCraig09 (talk) 14:35, 22 July 2023 (UTC)

I agree with the points made by Femke. I will elaborate a little bit more in the section "sub-issues" below.EMsmile (talk) 09:12, 25 July 2023 (UTC)

Sub-issues

Version 9 uploaded 25 July. Suggestions were implemented except as noted in discussion here.
(refresh & by-pass cache, for newest version)

Please answer inline within each topic, so we can keep discussions separate. I've implemented (late 22 July) many of the above suggestions (exceptions discussed as follows). I'll post a new version if more time passes without further comment below.

• Friendly names for positive/negative feedback. It seems consensus is to mention friendly names for positive/negative feedbacks in narrative text. I was going to supplement (not replace) the narrative text and image caption with friendly names, but I could not find a pair of friendly terms that are agreed on. Proposals so far are:

— reinforcing/balancing (EMsmile, source not specified)

— enhancing/weakening (IPCC)

— amplify/diminish (AR6 WGI TechSummary Fig TS.17)

— stabilizing/destabilizing (Sjsmith)

— amplifying/reducing (NASA)

— self-reinforcing/balancing (Femke, source not specified).

Does anyone know of an authoritative source for friendly names? —RCraig09 (talk) 22:14, 22 July 2023 (UTC)

• Both IPCC and NASA seem authoritative to me. Of the two, I think NASA doesn’t a much better job of explaining Climate Change concepts. Dtetta (talk) 22:24, 22 July 2023 (UTC)

I'm assuming you mean "NASA does a much better job...". —RCraig09 (talk) 22:27, 22 July 2023 (UTC)

The problem I've encountered is that sources use verbs to describe the feedbacks, but don't actually say the pos & neg feedbacks are "also called xxx and yyy feedbacks". It's possibly interpretive editorial overreach to say pos & neg feedbacks, esp. climate feedbacks, are also called anything. Our image caption and first paragraph of lead currently make the definitions clear. —RCraig09 (talk) 16:05, 24 July 2023 (UTC)

I am happy that Femke had the same comment that I had had, namely that "would omit the words "positive feedback" and "negative feedback" as jargon". In general, we can gently teach people about those terms by using the plainer wordings in different locations of the article. In particular, I don't like that we have a section heading called "Positive feedbacks", as I've said before. I don't mind if we use "self-reinforcing vs. balancing" or any of the other variations that you've listed. We could probably explain that there are different words used in the literature to describe these effects and that the "scientific terms" are positive/negative. EMsmile (talk) 09:29, 25 July 2023 (UTC)

Today I intend to introduce brief sentences immediately below the /* Positive feedbacks */ and /* Negative feedbacks */ sections summarizing how the respective feedbacks are defined, without changing the section names themselves. Since there are so many descriptive variations (list above), none are authoritative, and it's a distraction to list them all since "Positive" and "Negative" are the only terms that are ~universal. —RCraig09 (talk) 15:30, 25 July 2023 (UTC)

I've just uploaded Version 10, with descriptive terms (amplify warming) and (reduce warming) at the bottom, based on NASA terminology. The original authoritative terms, Positive feedbacks and Negative feedbacks, are retained. —RCraig09 (talk) 05:11, 26 July 2023 (UTC)

• Water vapor: Forcings vs Greenhouse gases. Initially I'm leaning toward retaining "water vapor" within the "Greenhouse gases" block because, well, it's a potent greenhouse gas (per NASA). The graphic's box merely says "Greenhouse gases", which makes me wonder why the "forcings" issue is determinative or even relevant. Concise explanation or graphical suggestions requested. —RCraig09 (talk) 22:22, 22 July 2023 (UTC)

I am confused about the water vapor issue so can't comment. But perhaps it comes down to the "impossible task" of having a concise/easy schematic for this. I still have my doubts that it's even worth trying to have such a schematic (see alos below).

The graphic presents a good sampling of feedbacks in relatively simple flowchart form. It's not "impossible". More below, in the "Gives the impression..." section. —RCraig09 (talk) 15:48, 25 July 2023 (UTC)

• "CO₂" vs "Carbon dioxide". I'm continuing to avoid use of subscripts because they require use of an SVG <tspan> element, which is suspected of involvement in ongoing SVG font rendering problems (software bug in Wikimedia projects). "Carbon dioxide" is also less jargony. —RCraig09 (talk) 04:09, 23 July 2023 (UTC)

If it's a matter of subscript then you could just make it CO2 without a subscript. In spoken language, "CO2 emissions" has become much more common than "carbon dioxide emissions" (for example). CO2 is in effect a 3-syllable word whereas "carbon dioxide" is a 5-syllable word. So I think CO2 would indeed be better here than carbon dioxide.

Counting syllables (!) is a formality, especially in a written diagram that isn't even being pronounced. Choosing to avoid a chemical formula in a layman's encyclopedia relates to accessability and is thus more substantive, especially when the chemical formula can't be a properly rendered chemical formula. —RCraig09 (talk) 15:37, 25 July 2023 (UTC)

• Removal of CO2 by ocean and plants. Dotted lines do lead to the "Greenhouse gases" block—as they should. —RCraig09 (talk) 04:15, 23 July 2023 (UTC)

Nowhere in the graph or caption can I find an explanation what the dotted lines versus the solid lines mean? Please put that in the the image caption. Also, I don't think those vertical and horizontal arrows in the middle of the schematic work well. It looks like there is a direct connection (double ended arrow) for the boxes, e.g. there is a double arrow from the box "snow cover loss" to the box "warmed Earth emits". EMsmile (talk) 09:29, 25 July 2023 (UTC)

Dashed lines merely meant feedback paths, but issue is avoided in Version 9, uploaded 25 July. —RCraig09 (talk) 15:50, 25 July 2023 (UTC)

• "Give the impression...". (... about + and - feedbacks being in balance, etc.). These "impression" comments are subjective, and at least for the time being I plan to leave the blocks as they are, since they show the science of CC feedbacks beyond the current era. Also, the blocks are visually/graphically balanced. —RCraig09 (talk) 04:33, 23 July 2023 (UTC)

I have a major problem with this as well and agree with Femke who said "Image gives the impression there are as many positive as negative feedbacks, which is not quite correct according to the article". I don't think the "visually/graphically balanced" explanation helps either. The schematic currently looks very balanced which is misleading/confusing and comes from the graphical setup with those boxes (one individual box for each mechanism). It might help to use only one single box on each side (so one on the positive side and one on the negative side) which each contains a bullet point list of mechanisms). This way it might become clearer (visually) that this is just a shortened list and that there is no "balance" whatsoever. It would also make the schematic simpler.

Overall, I value your attempts/determination to have such a schematic but I have lingering doubts that it could really be made to "work". Either it would have to be more detailed (e.g. the thickness of arrows indicating the magnitude of the effects) or it should be much simpler (just a box with a bullet point list on each side). EMsmile (talk) 09:29, 25 July 2023 (UTC)

It "works", right now. First, the article and its lead image should not be only about Earth and only about the present time period, even if that's what we might be inclined to think about; there will be different (im)balances at different places and different times. Three boxes on each side simply don't imply feedbacks are balanced; that is a subjective projection. Combining into boxed lists destroys the purpose of a graphic, especially one that distinguish feedbacks from each other. Many of your concerns can be addressed, if necessary, in captions and narrative text. —RCraig09 (talk) 15:48, 25 July 2023 (UTC)

Feedbacks to humans

Gore inconvenient truth loops

I do think that a feedback analysis of the links in Al Gore (2006). An inconvenient truth: the planetary emergency of global warming and what we can do about it. would be a useful contribution and i guess i agree that File:Gore inconvenient truth loops.png isn't high quality, so i've put it in the article about the book itself. i'd hoped that somebody might improve the image as it's a useful contribution to understanding the ultimately negative consequences of human population growth and technological development. if you know of anyone who'd like to pursue this, please let me know. Lee De Cola (talk) 13:52, 19 July 2023 (UTC)

Thanks for contributing, User:Ldecola. Al Gore's diagram may be less-than-professional in its graphical presentation, but it does begin to show the complexity of feedbacks in the climate system. I see its main value is to demonstrate "Climate feedbacks are complicated!"—a proposition that can be stated in text backed up by reliable sources. Other than improving the graphical representation a bit, I can't conceive of a way to improve the graphic in a way that would crystallize readers' understanding of feedbacks. —RCraig09 (talk) 16:51, 19 July 2023 (UTC)

Actually I regard the graphic's main point as that most of the important feedbacks to humans are negative and will reduce their numbers during this century, and we are seeing this playing out now. I think I'll post a similar graphic with page numbers on the AN INCONVENIENT TRUTH page, and see who reacts.Lee De Cola (talk) 18:27, 19 July 2023 (UTC)

The primary causes and the wide-ranging impacts of climate change. Some effects act as feedbacks that intensify climate change.

References

Hi Ldecola, that "Al Gore" graphic looks to me like a layperson or teacher has drawn it up - it just doesn't look very professional (unless its main point is to say "it's complicated!"...) I think there are better ones out there already, like this one on the right:

Also we have better articles for this topic, like effects of climate change and effects of climate change on human health. This article here is meant to be very much focused on only those very specific feedback effects, and will remain rather techy and sciency. The easier-to-understand information is more likely available to people at the range of articles that we already, which are called "effects of climate change on...". EMsmile (talk) 20:30, 19 July 2023 (UTC)

OK, we can drop the discussion of the graphic(s); but tho i'm an expert on global change, i AM anxious that Wikipedia may not be doing a good job of laying out the basics - but i expect that better heads than i are also aware of this. Lee De Cola (talk) 21:58, 19 July 2023 (UTC)

You Lee De Cola may find it easiest to go to the Talk Pages of particular articles, and make suggestions or "Edit requests" that you think might remedy your concerns. It's critical to be very specific in any suggestions you make. —RCraig09 (talk) 04:44, 20 July 2023 (UTC)

Some work done on the lead

I've just done some work on the lead:

• I used the table of content to come up with a summarised list of positive and negative feedbacks but it made me realised how poor some of the section headings, ordering and structure were. I've tried to make some quick changes (knowing that people already look at this article now for information) but I know this will require further work.
• I also tried to put them a bit more in order of "most important" to "least important". Please help if I got this wrong.
• Also, the information about the blackbody radiation is confusing. Femke had added: "it is typically not considered a feedback" whereas later in the main text we do list it under negative feedback and it says there: "It is called the Planck response, and sometimes considered a negative feedback". Here on the talk page, user InformationToKnowledge had quoted "Outgoing longwave radiation acts as the main major negative feedback, as hot things radiate more heat away". So I am confused now.
• Question: should we mention something about the lapse rate in the lead? Note: I have now moved that into a new section for things that can be either positive or negative. User:Sjsmith757 can you help further with the info on the lapse rate? EMsmile (talk) 22:06, 25 July 2023 (UTC)

@User:Bikesrcool or anyone else: could you help with cleaning up the content about blackbody radiation? Or has this already been sorted out? I see in the lead This blackbody radiation or Planck response has been identified as "the most fundamental feedback in the climate system" - do we need to provide both those terms or would one be sufficient? Are they the same thing? EMsmile (talk) 21:47, 23 January 2024 (UTC)

"Mathematical formulation" section

@Bikesrcool: WP:ONEDOWN is a general principle that I think editors in the climate change area intuitively follow, as we know we are communicating with the general public. Separately, I think the formulation itself is so similar to the early textual description, that a formulation doesn't really add anything more to the reader's knowledge. For these reasons, a "Mathematical formulation" section is not appropriate so early--and prominently--in the article. If it's retained in the article, I definitely think it should be moved down, before "See also" because all previous sections are meant for a lay audience and their likely concerns. I hope you'll consider these constructive remarks. —RCraig09 (talk) 04:54, 19 August 2023 (UTC)

Thanks for the constructive comment. The section has been moved to later for now. I feel the math is stripped down to a bare minimum while still succinctly linking the connected concepts of energy imbalance, forcings, and feedbacks. If placed earlier, the math complements the other introductory info in that sense, and would - in my opinion - be more logically situated before diving into the more gritty details of each individual component. Please also consider that highlighting a bit of low-level math can serve as a way of communicating the rigorous foundations of the science with the general public. Bikesrcool (talk) 15:40, 19 August 2023 (UTC)

@Bikesrcool: Thank you for being open minded. Discussions like recent ones at Talk:Greenhouse effect are in line with a community approach that the techy stuff should be placed lower in articles or in separate subsidiary articles. Generally, the presence of mathematical discussion might suggest credibility of the subject to the lay reader; however, a stripped-down version of the math that is just an alternative expression of the already-existing textual description, tends to suggest we are straining to "sell" a subject's credibility. (Conversely, going beyond the stripped-down version would be too techy for 99% of readers here.) In the present case, I think we've arrived at a good solution. —RCraig09 (talk) 15:57, 19 August 2023 (UTC)

I also have my doubts about this section. The formulae initially seem offputting but when reading through the section, I can see that they are very simple. Just putting the words into an equation. And then I wonder what's the point in even having them. I guess it's OK that they're so far down the article now but I would even be inclined to take the equations out and just leave the words (and in this case moving the section back towards the beginning again). I came to this article again because Bikesrcool was pondering over putting the same equations also at radiative forcing, see talk page there. EMsmile (talk) 21:43, 23 January 2024 (UTC)

Shouldn't the article title be "Climate change feedbacks", not "Climate change feedback"?

We aren't talking about a singular feedback. Even in our definitional sentence we begin by saying "Climate change feedbacks...". Sorry if this has been covered before, but it reads weird in the general climate change article as well, where climate forces are all plural except feedbacks. We have "aerosols", "clouds", "greenhouse gases", and then "climate change feedback". Any objection to doing a simple rename to this article? Efbrazil (talk) 15:49, 9 February 2024 (UTC)

• Agree. I'm OK either way, but the plural does inherently convey more information, instantly. —RCraig09 (talk) 21:48, 9 February 2024 (UTC)
• Strong support. I agree with you. EMsmile (talk) 14:31, 10 February 2024 (UTC)

Unclear sentence in the lead

Examples of some effects of global warming that can amplify (positive feedbacks) or reduce (negative feedbacks) global warming Observations and modeling studies indicate that there is a net positive feedback to Earth's current global warming.

I am trying to improve the reading ease of the lead but this sentence really baffles me, it seems messed up: These are arctic methane release from thawing permafrost, peat bogs and hydrates, abrupt increases in atmospheric methane, decomposition, peat decomposition, rainforest drying, forest fires, desertification. Seems like a messy list. Also, the paragraph in the lead about positive feedbacks (currently the second one) should line up better with the graphic on the right. I suggest to use the same ordering, and ensure the most important one is first (?). EMsmile (talk) 23:10, 15 March 2024 (UTC)

Update: this has been addressed in the meantime. EMsmile (talk) 21:09, 29 April 2024 (UTC)

References

Shouldn't the lead be changed to clarify that the total (net) feedback is negative when accounting for ALL feedbacks?

Quotation taken from top of page 978 AR6 WGI Chapter7 (and see table 7.10 at bottom of same page): "It is virtually certain that the net climate feedback is negative, primarily due to the Planck temperature response, indicating that climate acts to stabilize in response to radiative forcing imposed to the system. Supported by the level of confidence associated with the individual feedbacks, it is also virtually certain that the sum of the non-Planck feedbacks is positive. Based on Table 7.10 these climate feedbacks amplify the Planck temperature response by about 2.8 [1.9 to 5.9] times."

Likewise quoting from page 96 AR6 WGI Technical Summary (and see accompanying figure TS.17): "The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response (in the absence of feedbacks), also known as the Planck temperature response (virtually certain). Combining these feedbacks with the Planck response, the net climate feedback parameter is assessed to be –1.16 [–1.81 to –0.51] W m –2 °C –1 , which is slightly less negative than that inferred from the overall ECS assessment."

Could a simplified version of the Chapter 7 quotation replace the one now at the end of the lead?: It is virtually certain that the net climate feedback is currently negative and thus stabilizes climate over time, primarily due to Earth's blackbody radiation response. It is also virtually certain that the sum of all other feedbacks is positive and causes amplification of global warming. Bikesrcool (talk) 05:54, 14 April 2024 (UTC)

Could you make it more understandable for lay persons (given that it's the lead)? I don't really understand what is meant with "that the net climate feedback is currently negative" and "the sum of all other feedbacks". Perhaps you could be more explicit or give examples or use "in other words, xxx". Sometimes it even works to ask Chat-GPT how something could be said simpler. For example the first quote that you mentioned (p. 978) could be simplified as follows, Chat-GPT suggests "The overall effect of climate feedback is likely to be negative, mainly because of the Planck temperature response, meaning that the climate tends to stabilize when there's extra heat added to the system." I am not saying this is necessarily right or better, it's just something worth using for inspiration. Also given that the IPCC reports are not compatibly licenced so have to be paraphrased in any case. EMsmile (talk) 12:59, 14 April 2024 (UTC)

This is great input, thanks Bikesrcool! I tried to boil down that excellent synopsis on page 95 of AR6 WG1. As EMsmile says, best to avoid words like Planck response in the lead. Take a look and see if what I wrote works for you. Efbrazil (talk) 18:06, 14 April 2024 (UTC)

Ping to RCraig09, who has put in a lot of the content characterizing feedbacks as positive. Make sure you read that page of the IPCC report. The key point as I understand things is that feedbacks are net negative right now, but will become less negative as an effect of emissions continuing and/or time going by. Efbrazil (talk) 18:26, 14 April 2024 (UTC)

I don't think I provided the original motivation to even mention net positive vs. net negative feedback. I followed someone else's lead in even mentioning it, with my edit comment saying the content was added to avoid the inference expressed by another editor that positive and negative were balanced (I merely copied content from the lead text and placed it into the lead image caption; that particular sentence has just been deleted from the lead text.) The current lead image caption refers to AR5] (2014), which states on p. 82: "Therefore, there is high confidence that the net feedback is positive and the black body response of the climate to a forcing will therefore be amplified." I haven't studied AR6's apparent reversal of that conclusion—if they're talking about exactly the same issue. At this point, I think it wise to simply delete that sentence from the lead image caption until more knowledgeable editors have resolved the issue. —RCraig09 (talk) 19:21, 14 April 2024 (UTC)

Yeah, OK, let's go all the way to the top then and ask Femke :) Efbrazil (talk) 22:02, 14 April 2024 (UTC)

We should offer a consulting fee. :) —RCraig09 (talk) 22:18, 14 April 2024 (UTC)

With my mathematician's hat on: the Planck response is not a feedback in the mathematical sense. A feedback is the amplification of an initial response, and the Planck response is that initial response / reference system (https://www.atmos.albany.edu/daes/atmclasses/atm551/OtherReadingMaterials/Roe_AnnuRevEarth2009.pdf). So the AR6 was a bit sloppy in their wording; perhaps written by physicists rather than by mathematicians. We also repeat this misclassification in our lead. —Femke 🐦 (talk) 06:14, 15 April 2024 (UTC)

My recommendation is to defer to AR6 and the large body of supporting research which treats the generic Planck response and other Earth-specific feedbacks in a similar manner. To RCraig's comment: I understand there is no basic change between the technical conclusions of AR5 and AR6... just difference nuance/emphasis in the wording. To Femke's comment: Feedbacks can be talked about in different ways, that is why the math accompanying there scientific/physics definition is unavoidable and necessary to reign in other possible wanderings. The brief math formulation section of this article aligns IMO with the math/physics discussion of AR5, AR6, and the majority of other scientific literature that I've seen. These show that the Planck response is a feedback in the most fundamental mathematical sense as defined by the broader scientific community. As such, it is also often recognized to be a special response being ONLY a function of temperature. I am satisfied with the changes made by Efbrazil and RCraig to my post to this point and thank them. Bikesrcool (talk) 13:48, 15 April 2024 (UTC)

I'm not sure that's correct. AR6 usually talks about the Planck response, rather than the Planck feedback. In some graphs they have the Plack response plotted separately from the radiative feedbacks (for instance 7.20), implying that it's not a radiative feedback. They also state: "The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response, also known as the Planck temperature response (virtually certain)." Overall, they're a bit messy in their wording here. In literature on climate sensitivity (my former field), you often see the statement like "Without feedbacks, you'd have 1 degree of warming per doubling of CO2". That would be a non-sensical statement if the Planck response is considered a feedback. We could add the different perspectives to the article in footnotes, and use the more generic "Planck response" in our prose? —Femke 🐦 (talk) 15:29, 15 April 2024 (UTC)

What's interesting for the lead is whether the climate response to a linear increase in greenhouse gas emissions going forward is going to accelerate or decelerate, or whether the geographic locations of amplified warming will change at all. That means taking everything into account as much as possible- the carbon cycle, Planck response, and maybe even socioeconomic responses. Do we have something definitive on the holistic issue?

Whether the Planck response is defined as a feedback or not can go in the definition section along with whether the carbon cycle is considered a feedback. It sounds like we should both-sides those issues since there are references in either direction. However, for general interest on the topic, I think the right thing to do is mention everything, because the holistic picture is what matters in the end. Efbrazil (talk) 16:32, 15 April 2024 (UTC)

The carbon cycle is a feedback, it's just in a different categories of feedbacks than those we discuss when we talk about equilibrium climate sensitivity. Okay for me to change to Planck response? And write something about the Planck response sometimes being considered a feedback in a footnote? —Femke 🐦 (talk) 16:39, 15 April 2024 (UTC)

Obviously we'd love your help here, but I think the important thing we don't understand is the holistic effect. I'd love a paragraph in the lead saying "if GGE continue at their current rate, this is how the climate will change up to 2C, and this is what will happen up to 3C". I know that's a very difficult question to answer, which is why a lot of reports fall back to parsing individual components of the response instead of the overall response.

A lead that is instead focused on enumerating all possible feedbacks and saying what is or is not technically a feedback is a lot less interesting imho. As for the definitional issue, the carbon cycle is a "climate change feedback" if you are talking about the response to GGE, but if you are talking about feedbacks strictly in the context of given greenhouse gas levels (as AR4+ do with RCPs), then it is not. Efbrazil (talk) 16:52, 15 April 2024 (UTC)

Yeah, I agree definitions are not great in the lead. I think a footnote in the lead may work however. You think that's too much too? —Femke 🐦 (talk) 17:52, 15 April 2024 (UTC)

Sure, a footnote is good, plus probably some text in the definition and terminology section to back it up. Efbrazil (talk) 20:09, 15 April 2024 (UTC)

Also, it occurs to me that if feedbacks that included the Planck response as a feedback were net positive, then we could be talking about a runaway greenhouse effect, which nobody is predicting. Is that correct, or does a positive feedback value just mean warming would be amplified? Maybe a feedback value of over 1.0 = runaway greenhouse effect? The Internet is not helping with my blue sky questioning... Efbrazil (talk) 20:14, 15 April 2024 (UTC)

Yeah, I am also concerned about risk that a casual reader of the lead might associate a statement of net positive feedback with tipping or runaway. Whether the Planck response is properly classified as a feedback seems to me like a distraction in the bigger scope of the article, but I guess one could add a section acknowledging this nuance later down. Still when I think of perturbation theory, the two basic elements that I associate with it are just forcings and feedbacks... or forcings and responses. Thanks for all the great discussion of this topic. Bikesrcool (talk) 15:19, 16 April 2024 (UTC)

Good! I just did a fairly substantive edit pass on the last 3 paragraphs of the lead. Hopefully things are approaching OK. Efbrazil (talk) 17:43, 16 April 2024 (UTC)

I've just made some further tweaks to the lead to make it easier to understand. I hope I didn't change the meaning by mistake. There are still two sentences remaining which I find a bit hard to understand: Carbon cycle feedbacks are negative as carbon uptake increases when atmospheric concentrations increase. However, higher temperatures and saturation of carbon sinks will decrease that effect. (perhaps an example could help to clarify this? Sounds very abstract like this.).

And the lead length is a bit on the short side (344 words) but I guess that's OK as the overall article length is also short-ish (29 kB). EMsmile (talk) 21:09, 29 April 2024 (UTC)

It turns out that I never put this page on my watchlist, and had missed this discussion entirely. So, it's been quite a surprise for me when Efbrazil had reverted two paragraphs of my changes to the lead with the summary of: The last sentence was a clear run on sentence with bad readability. The Planck response is not a feedback and the IPCC explicitly says feedbacks will increase for the remainder of the century. Feedbacks are not "primarily estimated through models". The lead that was there was arrived at through extensive discussion- go slow on edits or open talk discussion please.

This is the comparison of the two versions.

Current wording

The reverted paragraphs

....The main positive feedback is that warming increases the amount of atmospheric water vapor, which is a powerful greenhouse gas.[5] Another positive feedback is the loss of reflective snow and ice cover. Positive carbon cycle feedbacks occur when organic matter burns or decays, releasing CO2 back into the atmosphere. Loss of organic matter can happen through rainforest drying, forest fires, and desertification. Methane can also be released into the atmosphere by thawing permafrost. The main cooling effect is called the Planck response, which comes from the Stefan–Boltzmann law. It states that the total energy radiated per unit surface area per unit time is directly proportional to the fourth power of the black body's temperature. The carbon cycle acts a negative feedback as it absorbs more than half of CO2 emissions every year. Atmospheric CO2 gets absorbed into rocks and into plants. It also gets dissolved in the ocean where it leads to ocean acidification. There are several types feedbacks: physical feedbacks, biological feedbacks and carbon cycle feedbacks. Calculations can give different results depending on the time frame and location that is used. Carbon cycle feedbacks are negative, which means that as atmospheric concentrations increase, carbon uptake also increases. However, higher temperatures and saturation of carbon sinks decrease that negative feedback effect. Overall feedbacks are expected to trend in a positive direction for the near future, though the Planck response will become increasingly negative as the planet warms.[6]: 94–95  There is no threat of a runaway greenhouse effect from current climate change.

....Feedbacks are generally divided into purely physical and partially biological (i.e. biogeophysical and biogeochemical.) The former include cloud feedback, ice-albedo feedback, Planck response feedback as well as the lapse rate and water vapor feedbacks. The latter mostly consist of feedbacks associated with the carbon sinks and the carbon cycle. Sometimes, feedbacks associated with the ice sheets are treated separately from either, because it takes multiple centuries before they become apparent, whereas the others have a substantial role within decades. Feedback strengths and relationships are primarily estimated through global climate models, with their estimates calibrated against observational data whenever possible. "Fine-scale" modelling devoted to specific processes also exists, and has been used more widely starting from 2010s. The overall sum of climate feedbacks is negative, meaning that they make the warming slower than it would be otherwise. It also means that runaway greenhouse effect effectively cannot occur due to anthropogenic climate change. This is largely because of the Planck rate negative feedback, which is several times larger than any other singular feedback. Additionally, the carbon cycle already absorbs a little over half of annual CO2 emissions, and its ability to do so scales almost in proportion to emissions. However, as the warming increases, it amplifies positive feedbacks - like the ice-albedo feedback and soil carbon feedback, or the various feedbacks which increase atmospheric methane concentrations - more than the negative ones, so the warming is slowed less than it would have been at a cooler initial state.

Now...

and the IPCC explicitly says feedbacks will increase for the remainder of the century. - Which is exactly what the last sentence was meant to say - the one which you concluded lacked readability.

The IPCC also explicitly says that the sum of all feedbacks is negative, yet as already pointed out by Bikesarecool above, this is not currently mentioned at all. And speaking of things which were explicitly mentioned by the IPCC...

Feedbacks are not "primarily estimated through models". - Wanna bet?

Up until AR5, process understanding and quantification of feedback mechanisms were based primarily on global climate models. Since AR5, the scientific community has undertaken a wealth of alternative approaches, including observational and fine-scale modelling approaches. - AR6, WG1, CH7, 967

The Planck response is not a feedback - and this is where the discussion above gets really confusing. So, Bikesarecool has already provided an IPCC quote where it is considered a feedback. If necessary, I can provide another. EDIT: There it is.

The Planck response represents the additional thermal or longwave (LW) emission to space arising from vertically uniform warming of the surface and the atmosphere. The Planck response αP, often called the Planck feedback, plays a fundamental stabilizing role in Earth’s climate and has a value that is strongly negative: a warmer planet radiates more energy to space. - AR6, WG1, CH7, 968

Yet, apparently, the discussion so far has opted to believe that the IPCC as a whole has made a mistake, based on...Femke's individual opinion and an Annual Reviews article from 2009? Sure, this here

It is also worth mentioning that what even counts as a feedback depends on the definition of the reference system. For example, the Stefan-Boltzman relation is often described as a negative climate feedback acting to regulate temperature anomalies. In fact, for a blackbody planet, which is the simplest imaginable reference system for the climate that is still meaningful, the Stefan-Boltzman relation is part of the reference system and therefore not a feedback at all. These are not semantic or esoteric issues—the quantitative intercomparison of different feedbacks can be done only when the reference system is defined and held constant

Is interesting. Should this, written by just one professor, be given credence over the wording of the world's premier scientific body, over a decade later? I doubt it. Moreover, here is something else from the earlier discussion: (quote template keeps bugging out here, for some reason.)

"Also, it occurs to me that if feedbacks that included the Planck response as a feedback were net positive, then we could be talking about a runaway greenhouse effect, which nobody is predicting. Is that correct, or does a positive feedback value just mean warming would be amplified? Maybe a feedback value of over 1.0 = runaway greenhouse effect?..."

I believe that (the bolded part) actually is the case? I would quote myself from a discussion we had here last year (now archived):

According to the leading expert on climate feedback loops and tipping points, Dr. Adam Armstrong McKay (the lead author of last year's Science assessment of tipping points):

"Outgoing longwave radiation acts as the main major negative feedback, as hot things radiate more heat away. Positive feedbacks do not inevitably lead to runaway warming, as negative feedbacks will eventually counter them – if there were no negative feedbacks Earth would have become as hot as Venus long ago."

So, it probably shouldn't matter given the opinion of the IPCC alone, but the lead author of this paper we cite very extensively, and almost certainly one of the top 5 experts on the subject worldwide, also happens to describe the Planck response/blackbody radiation as a feedback. Are we going to argue against this too? (Trivia: I think he and Femke might be at the same research institution, so there is conceivably a chance they could talk this over in person?) InformationToKnowledge (talk) 12:34, 15 May 2024 (UTC)

P.S. This isn't related to the reverted paragraphs, but I might as well address this matter now anyway:

What's interesting for the lead is whether the climate response to a linear increase in greenhouse gas emissions going forward is going to accelerate or decelerate, or whether the geographic locations of amplified warming will change at all. - I have already answered this question in the lead of Causes of climate change (which apparently wasn't read very closely by anyone here?)

The warming from the greenhouse effect has a logarithmic relationship with the concentration of greenhouse gases. This means that every additional fraction of CO₂ and the other greenhouse gases in the atmosphere has a slightly smaller warming effect than the fractions before it as the total concentration increases. However, only around half of CO₂ emissions continually reside in the atmosphere in the first place, as the other half is quickly absorbed by carbon sinks in the land and oceans.

As the warming from CO₂ increases, carbon sinks absorb a smaller fraction of total emissions, while the "fast" climate change feedbacks amplify greenhouse gas warming. Thus, both effects are considered to each other out, and the warming from each unit of CO₂ emitted by humans increases temperature in linear proportion to the total amount of emissions.

This is based on the following IPCC paragraphs:

As cumulative emissions increase, weakening land and ocean carbon sinks increase the airborne fraction of CO2 emissions (see Figure 5.25), but each unit increase in atmospheric CO2 has a smaller effect on global temperature owing to the logarithmic relationship between CO2 and its radiative forcing (Matthews et al., 2009; Etminan et al., 2016). At high values of cumulative emissions, some models simulate less warming per unit CO2 emitted, suggesting that the saturation of CO2 radiative forcing becomes more important than the effect of weakened carbon sinks (Herrington and Zickfeld, 2014; Leduc et al., 2015). The behaviour of carbon sinks at high emissions levels remains uncertain, as models used to assess the limits of the TCRE show a large spread in net land carbon balance (Section 5.4.5), and most estimates did not include the effect of permafrost carbon feedbacks (Sections 5.5.1.2.3 and 5.4). The latter would tend to further increase the airborne fraction at high cumulative emissions levels, and could therefore extend the window of linearity to higher total amounts of emissions (MacDougall et al., 2015). Leduc et al. (2016) suggested further that a declining strength of snow and sea ice feedbacks in a warmer world would also contribute to a smaller TCRE at high amounts of cumulative emissions. However, Tokarska et al. (2016) suggested that a large decrease in TCRE for high cumulative emissions is only associated with some EMICs; in the four ESMs analysed in their study, the TCRE remained approximately constant up to 5000 PgC, owing to stronger declines in the efficiency of ocean heat uptake in ESMs compared to EMICs.

Overall, there is high agreement between multiple lines of evidence (robust evidence) resulting in high confidence that TCRE remains constant for the domain of increasing cumulative CO2 emissions until at least 1500 PgC, with medium confidence of it remaining constant up to 3000 PgC because of less agreement across available lines of evidence. - AR6, WG1, CH5, 746

TLDR; climate response will remain linear for the foreseeable future, and once it is no longer linear, it is more likely to decelerate rather than accelerate. InformationToKnowledge (talk) 12:37, 15 May 2024 (UTC)

P.P.S. For all of the fairly dense and arguably not-layman-relevant discussion that dominates our article on the greenhouse effect - with all its mentions of energy flux and top-of-the-atmosphere and what not - it does not seem to say anything about its logarithmic nature at all. Perhaps it is time to finally rectify this omission? If so, would we explain the logarithmic growth as a property caused by the Planck response (and correspondingly mention it here as well?), or is there some other factor? InformationToKnowledge (talk) 12:44, 15 May 2024 (UTC)

No objections, but I think that's a separate discussion best raised on that talk page there. Efbrazil (talk) 18:36, 15 May 2024 (UTC)

Thanks for opening this discussion. The comment reverting that edit area had to be very abbreviated as per comment lengths.

As for saying feedbacks are "primarily estimated through models": The issue is that's wording that climate deniers use. Their argument is that all this climate stuff is just apocalypic modeling by scientists wanting funding or fame and not a reflection of the real world. Think of the middle school education person encountering this article. We need to first establish the real world data and the physical grounding for all we're saying. It is fine to say that models built on top of those fundamentals are how we estimate feedback outcomes, but only later. So it's a minor issue, but I'd rather the lead focus on fundamentals.

As for the Planck response being a feedback: There are sources in the IPCC going either way on the issue, so we should not be stating that the Planck response is a feedback. Let me know if you disagree and I can dig up some IPCC talk that reflects the alternate view that backs what Femke said. The lead text that I reverted to split the difference to get to consensus. It talks about Planck response but never says it is a feedback, and I think we need to stick with that wording unless there is consensus to the contrary.

You do a great job as usual of highlighting the issues that caused the lead text that's there now to end fairly ambiguously about which direction feedbacks are headed. I am certainly happy with adding a well sourced summary sentence saying that climate response will remain linear for the foreseeable future. I was looking for something like that myself as you could tell in quoting me up above. Just make sure any claims you make are well sourced.

To be clear, my reverting your text wasn't about saying it was all wrong, only that I had certain disagreements. If you make changes more incrementally it's better for everyone, because that way each change can be reviewed in isolation. If there's a big pivot or issue you want to address then the talk page is a great place to do it. Efbrazil (talk) 18:33, 15 May 2024 (UTC)

Let me know if you disagree and I can dig up some IPCC talk that reflects the alternate view that backs what Femke said. - Please do. Having said that, this is secondary to the question at the top of this section - about the direction of the net sum of feedbacks. As you might have noticed, I included another prominent reference which says that the net feedback is negative, but I don't know if this is going to make a difference. If some editors here already find the IPCC text "ambiguous", would a single paper on top of it (even from Nature Geoscience) matter? Would 3, 5, or 10 more matter?

Having said that, I am also open to the argument that the only thing we really need to say in the lead is about the (lack of) direction in the net climate response to emissions (which doesn't mean that the rate of observed warming will stay linear, since a massive increase in emissions has already happened yet wouldn't be fully felt until the next couple of decades.) Would that also mean that we should use a similar wording in the lead here, at Causes of climate change, at greenhouse effect and perhaps in the lead of other related articles like climate sensitivity?

As for saying feedbacks are "primarily estimated through models": The issue is that's wording that climate deniers use. Hmm, my primary impression to date has been the opposite - stupid claims on various social media that "[feedback which has been known for many decades] isn't in the models and so there'll "actually" be this much more warming than what the IPCC says." I noticed that the individual feedback sub-sections already had little "This feedback is in the models" disclaimers (which I tried to rework into stronger and more specific sentences), so at least some editors are clearly aware of this issue. I wonder if anyone else wants to weigh in? InformationToKnowledge (talk) 02:43, 16 May 2024 (UTC)

A few references to consider. This text says that net feedbacks are heading in a positive direction:

IPCC AR6 WG1 Technical Summary 2021, p. 93: Feedback processes are expected to become more positive overall (more amplifying of global surface temperature changes) on multi-decadal time scales as the spatial pattern of surface warming evolves and global surface temperature increases.

Regarding whether the Planck response is a feedback, here is text that says Planck response is a base climate response and not a feedback (there are counterexamples as well):

IPCC AR6 WG1 Technical Summary 2021, p. 95: The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response (in the absence of feedbacks), also known as the Planck temperature response.

In general, Planck response is only mentioned very sparingly in the report. Whether it is considered a feedback impacts how to interpret the IPCC report and how to compose the lead. Does that page 93 text include Planck response when saying "more positive overall"? That's where the ambiguity comes in. Efbrazil (talk) 15:14, 16 May 2024 (UTC)

Excuuuuse me... Let's step back. Almost ~5000 words have been invested here, trying to un-ambiguate what is an ambiguous term. Maybe it would be best to avoid broad statements in the lead (about net positive vs net negative), and instead explain the ambiguity in a dedicated section lower in the article. —RCraig09 (talk) 16:21, 16 May 2024 (UTC)

That's the current state of the article, more or less. I think I2K is trying for clarity, which would be great. The easiest claim to make is that the IPCC is a hot mess when it comes to this issue. AR6 WG1 TS Page 93 has two declarative statements defining what a feedback is and they are completely at odds with each other. Efbrazil (talk) 19:31, 16 May 2024 (UTC)

I think there is no consensus in this discussion to remove the key statement about the net effect of feedbacks from the text of multiple articles. When there is disagreement we revert to the status quo ante. I don't think this article is neutral without this statement in the lead. Page 93 and 94 of the TS don't seem internally inconsistent. The net effect is mentioned implicitly on p93 one and explicilty on p94, in accordance with each other. —Femke 🐦 (talk) 18:43, 19 May 2024 (UTC)

Sorry, I had the page number wrong, it's page 95 of the TS, not page 93. The text there is confusing as it says the Planck response is not a feedback, but it is part of net feedbacks. Here's the word salad:

The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response (in the absence of feedbacks), also known as the Planck temperature response (virtually certain). Combining these feedbacks with the Planck response, the net climate feedback parameter is assessed to be –1.16 [–1.81 to –0.51] W m–2 °C–1, which is slightly less negative than that inferred from the overall ECS assessment. The combined water vapour and lapse rate feedback makes the largest single contribution to global warming, whereas the cloud feedback remains the largest contribution to overall uncertainty. Due to the state-dependence of feedbacks, as evidenced from paleoclimate observations and from models, the net feedback parameter will increase (become less negative) as global temperature increases. Furthermore, on long time scales the ice-sheet feedback parameter is very likely positive, promoting additional warming on millennial time scales as ice sheets come into equilibrium with the forcing.

The main point we could run with is that "the net feedback parameter will increase (become less negative) as global temperature increases". They explicitly say that includes Planck response. Efbrazil (talk) 22:05, 19 May 2024 (UTC)

Again, that was the exact purpose of the phrase you reverted as The last sentence was a clear run on sentence with bad readability.

You know, this one: However, as the warming increases, it amplifies positive feedbacks - like the ice-albedo feedback and soil carbon feedback, or the various feedbacks which increase atmospheric methane concentrations - more than the negative ones, so the warming is slowed less than it would have been at a cooler initial state.

OK, it probably was too complex and should have been split, but this is what it was meant to say (and while avoiding close paraphrasing.)

Anyway, here is something you should pay attention to. I have been in contact with Kevin Trenberth, a lead author of three IPCC reports, (you can double-check by asking @EMsmile) and he agrees that the net climate feedback is negative and it can only be considered positive when the Planck response is de-emphasized and moved into the background - which is an approach he dislikes.

Granted, this isn't very easy to summarize. After a couple of attempts, I got to a wording he thinks is "OK".

The overall sum of all climate feedbacks is negative, meaning that, for a warming climate, the warming is slower than it would be otherwise. This due to the strongly negative Planck radiative rate feedback, which is several times larger than any other singular feedback. In estimates where Planck rate response is described as part of the baseline climate system, the net sum of feedbacks is positive, but its stabilizing effect is still assumed implicitly.

You may think there is a way to improve this sentence structure, etc., but hopefully this settles the fundamental argument. InformationToKnowledge (talk) 12:26, 20 May 2024 (UTC)

Page 95 of the TS says that the Planck response is part of the climate feedback "parameter", which is also called the climate sensitivity parameter. It explicitly says this parameter is the sum of feedbacks and the Planck response. There is no contradiction there. It's just much easier to add these in an equation.

I object to the new text. Apart from calling something a feedback which the IPCC says isn't one, the word "otherwise" is describing a hypothetical with infinite warming. It doesn't make sense to compare it with that. I'm also not sure we should be using positive or negative here. There is no consistent Sign convention around the climate sensitivity/feedback parameter, even though the convention the IPCC use is more common. Better to describe the net effect as amplifying. —Femke 🐦 (talk) 16:10, 20 May 2024 (UTC)

I went through I2K's text again and tried to pull out some of the parts I think are good additions and also tried to factor in what femke is saying. Here is a cut at rewriting the last paragraph:

Calculating climate sensitivity requires accounting for the planck response, radiative feedbacks, and carbon cycle feedbacks. Overall, climate sensitivity is expected to increase in the near future, although there is no threat of a runaway greenhouse effect. Time frames and emission rates impact estimates. Feedbacks associated with ice sheets can take centuries, whereas the other feedbacks have a substantial role within decades. Carbon cycle feedbacks are negative in the short term because carbon uptake increases as atmospheric concentrations increase, but over the long term higher temperatures and carbon sink saturation are reducing that negative effect. Feedbacks can also result in localized differences, such as increased warming in locations with reduced snow and ice. Feedback strengths and relationships are estimated through global climate models, with their estimates calibrated against observational data whenever possible. Efbrazil (talk) 17:07, 20 May 2024 (UTC)

I'm mostly happy with this compromise. One thing: carbon feedbacks are climate system feedbacks. The grouping is usually physical vs carbon vs other biogeochemical. —Femke 🐦 (talk) 18:55, 20 May 2024 (UTC)

I changed the proposed text above to say "radiative feedbacks" instead of "climate system feedbacks"...Efbrazil (talk) 19:56, 20 May 2024 (UTC)

New lead graphic proposal

We could adapt this image to a compressed form that is good for smartphones / thumbnails: https://www.ipcc.ch/report/ar6/wg1/downloads/figures/IPCC_AR6_WGI_TS_Figure_17.png

Chart (b) of that image can be cut as the content is already represented in chart (a) and isn't very consequential. The naming is a torture though, so I'd rename the item from "Biophysical and non-CO2 biogeochemical" to the somewhat simpler "Non-CO2 biological".

It's annoying that they have "total" for climate system feedbacks but do not provide a total for carbon cycle feedbacks. I'd just leave out "total" as a result.

Charts (a) and (c) could then be combined as the x axis is the same.

Also, I'm not sure we should have the jargony "planck" in there, so maybe add a parenthetical explanation saying (thermal radiation).

Finally, there's the discussion up above that we should account for, namely that planck response is not technically a feedback and that the carbon cycle is part of the climate system. So that leaves something like this:

Title: Factors influencing climate sensitivity

Rows, where "Radiative feedbacks" and "Carbon cycle feedbacks" would just be headers with no data:

Planck (thermal radiation)

Radiative feedbacks

• Water vapor and lapse rate
• Surface albedo
• Clouds
• Non-CO2 biological

Carbon cycle feedbacks

• Land carbon response to CO2
• Ocean carbon response to CO2
• Land carbon response to climate
• Ocean carbon response to climate

Finally, for the X axis label, simply have 2 arrows pointing off center that say "Negative feedback" and "Positive feedback", like the top of the IPCC chart does. I don't see a point in articulating "Climate feedback parameter (WM-2 C-1)" and the numbers as those will mean nothing to people. The caption and graphic description can get into all that. The real point of the graphic is to highlight the major factors to consider. Efbrazil (talk) 23:33, 20 May 2024 (UTC)

July 2022+ feedbacks diagram

Oh, now I see. As I mentioned today on my User Talk Page, I'm willing to create charts of part (a) and of part (c) of TS-17 and can do so within days.

However, such a chart is much more techy than the July 2022+ conceptual diagram (at right) that's presently in the lead. The present diagram's common English language and color-coded areas are more readily understood by the lay audience for whose benefit this website exists. Quantification, bar charts, confidence intervals / error bars, and explanations of "feedback parameters" W/(m^2*°C) can go lower in the article, possibly as high as the /* Physical feedbacks */ section. Also, the controversy of whether Planck is truly considered a feedback, and the WP:SYNTH issue of combining (a) and (c) in the same diagram, further argues against such detailed quantitative portrayals in the introduction. —RCraig09 (talk) 03:58, 21 May 2024 (UTC)